1. Field of the Invention
The present invention relates to an image forming apparatus and a toner replenishing method to replenish toner to a developing device from a toner container.
2. Description of the Related Art
There are some electro-photographic image forming apparatus using a toner bottle or a toner cartridge as a toner container. In such an image forming apparatus, when a toner in a toner container decreases largely, a toner replenishing amount per one replenishing motion decreases continuously. The state where a preset toner density could not be reached even when a toner was replenished for a given length of time is regarded as a toner empty state. At this toner empty state, the image forming apparatus reports a user to exchange the toner container such as a toner bottle, a toner cartridge, etc.
Based on this report, the user removes an empty toner container from the main body of the image forming apparatus and exchanges it with a new toner container filled with toner. At this time, the empty container removed from the main body is often discarded in many cases.
In the toner empty state described above, over ten grams of toner adhered to the inner surface of the toner container is left as residual toner. In spite of this, there was such a problem that a toner container containing some residual toner was discarded.
For this problem, a method to use a spare toner by counter rotating a toner bottle is proposed, for example, a method disclosed in the Japanese Patent Application Publication No. 2002-139905.
This method, however, is merely to rotate a toner bottle in the reverse direction by several rotations in order to move spare toner. Further, there is also a conventional technology to give a mechanical vibration by providing a separate mechanism. For this technology, a mechanism must be provided to the main body of an image forming apparatus for this purpose and there were such problems as cost increase, securing of installing place, etc. Further, there are some users of image forming apparatus, who remove a toner container from an image forming apparatus and drop residual toners in containers by giving a shock to the toner container when a toner container was emptied. However, there were such troubles that during this period, the apparatus must be stopped and its efficiency drop, clothes or hands are made dirty when removing and hitting a toner container;